Fix string convention

cupy/core/carray.pxi

@@ -124,7 +124,7 @@ cpdef str _get_header_source():
 
 cpdef function.Module compile_with_cache(
         str source, tuple options=(), arch=None, cachd_dir=None,
-        prepend_cupy_headers=True, backend="nvrtc"):
+        prepend_cupy_headers=True, backend='nvrtc'):
     if prepend_cupy_headers:
         source = _cupy_header + source
     extra_source = _get_header_source()

cupy/core/raw.pyx

@@ -25,7 +25,7 @@ cdef class RawKernel:
 
     """
 
-    def __init__(self, code, name, options=(), backend="nvrtc"):
+    def __init__(self, code, name, options=(), backend='nvrtc'):
         if isinstance(code, six.binary_type):
             code = code.decode('UTF-8')
         if isinstance(name, six.binary_type):
@@ -58,7 +58,7 @@ cdef class RawKernel:
 
 
 @cupy.util.memoize(for_each_device=True)
-def _get_raw_kernel(code, name, options=(), backend="nvrtc"):
+def _get_raw_kernel(code, name, options=(), backend='nvrtc'):
     module = cupy.core.core.compile_with_cache(
         code, options, prepend_cupy_headers=False, backend=backend)
     return module.get_function(name)

cupy/cuda/compiler.py

@@ -123,7 +123,7 @@ def compile_using_nvcc(source, options=(), arch=None, filename='kern.cu'):
     cmd = ['nvcc', '--cubin', arch_str] + list(options)
 
     with TemporaryDirectory() as root_dir:
-        first_part = filename.split(".")[0]
+        first_part = filename.split('.')[0]
 
         path = os.path.join(root_dir, first_part)
         cu_path = '%s.cu' % path
@@ -174,7 +174,7 @@ def _preprocess(source, options, arch, backend):
                 e.dump(sys.stderr)
             raise
     else:
-        raise ValueError("Invalid backend %s" % backend)
+        raise ValueError('Invalid backend %s' % backend)
 
     assert isinstance(result, six.text_type)
     return result
@@ -191,7 +191,7 @@ def get_cache_dir():
 
 
 def compile_with_cache(source, options=(), arch=None, cache_dir=None,
-                       extra_source=None, backend="nvrtc"):
+                       extra_source=None, backend='nvrtc'):
     # NVRTC does not use extra_source. extra_source is used for cache key.
     global _empty_file_preprocess_cache
     if cache_dir is None:
@@ -237,15 +237,15 @@ def compile_with_cache(source, options=(), arch=None, cache_dir=None,
                 mod.load(cubin)
                 return mod
 
-    if backend == "nvrtc":
+    if backend == 'nvrtc':
         ptx = compile_using_nvrtc(source, options, arch, name + '.cu')
         ls = function.LinkState()
         ls.add_ptr_data(ptx, u'cupy.ptx')
         cubin = ls.complete()
-    elif backend == "nvcc":
+    elif backend == 'nvcc':
         cubin = compile_using_nvcc(source, options, arch, name + '.cu')
     else:
-        raise ValueError("Invalid backend %s" % backend)
+        raise ValueError('Invalid backend %s' % backend)
 
     cubin_hash = six.b(hashlib.md5(cubin).hexdigest())
 

tests/cupy_tests/core_tests/test_raw.py

@@ -22,7 +22,7 @@ def test_basic(self):
         assert (y == x1 + x2).all()
 
     def test_backends(self):
-        for backend in ("nvrtc", "nvcc"):
+        for backend in ('nvrtc', 'nvcc'):
             kern = cupy.RawKernel(_test_source, 'test_sum', backend=backend)
             x1 = cupy.arange(100, dtype=cupy.float32).reshape(10, 10)
             x2 = cupy.ones((10, 10), dtype=cupy.float32)